Re: xargs verses exec
- From: "Radoulov, Dimitre" <cichomitiko@xxxxxxxxx>
- To: Joel.Patterson@xxxxxxxxxxx
- Date: Tue, 24 Jul 2012 21:24:06 +0200
Hi Joel,
On 24/07/2012 20:50, Joel.Patterson@xxxxxxxxxxx wrote:
> It has come time to switch to xargs instead of exec. I have found two issues
> with xargs, but I'll only ask one now.
>
> Say I change to ORACLE BASE and do a find on 'all the subdirectories' piping
> through xargs, but... there are no files that meet the criteria -- say the
> extension is ".abc".
>
> cd ${ORACLE_BASE}
> find */cdump -name "*.abc" -type f -mtime +40 -print | xargs ls -ltr
>
> Then, the find command comes back with the contents of the ${ORACLE_BASE}
> directory.
GNU xargs has the -r/--no-run-if-empty option for this :).
That said, _most_ find implementations support the {} + syntax for xargs
emulation:
-exec command {} +
This variant of the -exec option runs the specified
command on the selected files, but the
command line is built by appending each selected file
name at the end; the total number of
invocations of the command will be much less than the
number of matched files. The command
line is built in much the same way that xargs builds its
command lines. Only one instance of
'{}' is allowed within the command. The command is
executed in the starting directory.
Note also that with the above syntax you're completely bypassing the
shell (i.e. no shell special/IFS characters related problems).
Regards
Dimitre
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